1. Field of the Invention
The present invention is related to a graphite oxide and graphene preparation method, particularly to a graphite oxide and graphene preparation method with plasma electrolytic process.
2. Description of the Prior Art
Graphene is a newly discovered carbon nanomaterial and provided with many excellent properties such as linear spectrum, high electron mobility, the unique optical properties, high elasticity, sturdiness and single atomic width. The graphene is viewed as a breakthrough nanomaterial for applications in optoelectronics, energy and chemical material fields.
Since the graphite oxide can be used in manufacturing graphene, it has attracted great attention. The chemical reduction of the exfoliated graphite oxide has been widely considered to be the most promising approach for a large-scale production of graphene. Such process involves (I) oxidation of graphite to graphite oxide (GO) (II) exfoliation of GO through ultrasonication or thermal treatment to yield graphene oxide; and (III) chemical reduction of graphene oxide to a graphitic network of sp2-hybridized carbon atoms.
However, in the prior art, the mixtures of strong oxidants and concentrated acids are required for preparing GO and thus graphene in large scale, and strong acids are dangerous and unstable during the processing, requiring extra safety precautions. Moreover, the discharge of large quantity of acidic waste poses an environmental risk. Therefore, the preparation method of the graphite oxide still needs substantial improvements.
Paulmier. et al (Thin Solid Films 515(5):pp. 2926-2934) disclosed a cathode plasma electrolytic method to deposit the nano-crystalline graphite films. Paulmier placed graphite on the anode although Paulmier taught deposit carbon film on the cathode. Richenderfer et al (http://www.phys.cwru.edu/undergrad/Senior%20Projects/papers/papers2012/Richenderfer—Gao.pdf) taught that deposit carbon film on the cathode and promote the exfoliation of the graphite by passing the current through the electrolyte, but placed graphite on the anode and employed micro-plasma as the electrode to enhance the electric filed. Also, Richenderfer used acidic electrolyte (containing HCl) along with an electrochemical method that in needs of concentrated acid for reaction. Since the acidic solution manipulation in Richenderferes method is required, it leaves room for improvement.
In summary, it is now a current goal to develop a graphite oxide/graphene preparation method with advantages such as high efficiency and environmentally friendliness.